DAMASCUS, Syria — The United Nations Security Council on Thursday called on Syria to “urgently” move to keep an April 10 deadline to withdraw troops and weapons from protest cities.

The 15-nation council, including Russia and China, agreed a statement putting new pressure on President Bashar al Assad to end his offensive on protesters and opposition groups, which the UN says has left at least 9,000 dead in the past year.

The council gave strong new backing to a peace plan by United Nations-Arab League envoy Kofi Annan, who says Syria agreed an April 10 deadline to withdraw its troops and heavy weapons from main cities.

If this is carried out, Annan will then give the government and opposition groups 48 hours to end all hostilities.

The Security Council statement “calls upon the Syrian government to implement urgently and visibly its commitments” made to Annan to take the steps toward a cessation of hostilities.

It also calls for Syria to start a two-hour daily pause in hostilities and allow immediate humanitarian access.

The council said that depending on Annan’s reports on what Assad has carried out, it will “consider further steps as appropriate.”

The Security Council, which has been badly divided on Syria, gave its new boost to Annan’s peace mission just before the special envoy briefed the UN General Assembly on his efforts to halt the government clampdown.

Annan told the General Assembly that Syria claims to have carried out a “partial withdrawal” of three cities, but he added that “alarming” levels of casualties were still being reported in the country.

Annan said the Syrian government told him the partial withdrawal had occurred in Idlib, Zabadani and Daraa. But he told the General Assembly that this had not been confirmed.

Thursday’s Security Council statement was softened at Russia’s demand, diplomats involved in the talks said. Russia and China have vetoed two previous full resolutions on Syria.

An initial proposal by Western countries that the council “demands” that Syria pull back its troops and heavy weapons was changed to “calls,” and “verifiably” was changed to “visibly.”

Western nations have expressed deep skepticism that Syria will act on the deadline.

Diplomats said, however, that the council would face a new battle if Annan says that Syria has failed to keep the agreement and calls for UN sanctions. Russia and China are unlikely to agree to any sanctions, they said.

Earlier Thursday, there were signs that the Syrian regime may not be willing to abide by the April 10 deadline.

The pro-government daily newspaper Al Watan quoted a government official as saying the regime is not bound by the deadline to withdraw its troops from strife-torn areas.

“There is no set date or deadline,” the unnamed official said. “April 10 is the date set for the beginning, not the end, of the withdrawal of troops, and it does not constitute a deadline.”